Problem: Solve for $x$ : $6x + 9 = 9x + 10$
Solution: Subtract $6x$ from both sides: $(6x + 9) - 6x = (9x + 10) - 6x$ $9 = 3x + 10$ Subtract $10$ from both sides: $9 - 10 = (3x + 10) - 10$ $-1 = 3x$ Divide both sides by $3$ $\dfrac{-1}{3} = \dfrac{3x}{3}$ Simplify. $-\dfrac{1}{3} = x$